Prediction of Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease: Correlation with Quantitative CT Parameters

• Published in: Korean journal of radiology 2019, 20(4), , pp.683-692
• Main Authors: Koo, Hyun Jung, Lee, Sang Min, Seo, Joon Beom, Kim, Namkug, Oh, Sang Young, Lee, Jae Seung, Oh, Yeon Mok
• Format: Article
• Language: English
• Subjects: Aged; Body mass index; Bronchitis; Chronic obstructive pulmonary disease; Emphysema; Female; Forced Expiratory Volume; Humans; Linear Models; Lung - diagnostic imaging; Lung - physiopathology; Lung diseases; Male; Middle Aged; Patients; Pulmonary Disease, Chronic Obstructive - pathology; Regression analysis; Respiratory Function Tests; Severity of Illness Index; Software; Spirometry; Thoracic Imaging; Tomography, X-Ray Computed; Tuberculosis; 방사선과학
• ISSN: 1229-6929; 2005-8330
• DOI: 10.3348/kjr.2018.0391

We aimed to evaluate correlations between computed tomography (CT) parameters and pulmonary function test (PFT) parameters according to disease severity in patients with chronic obstructive pulmonary disease (COPD), and to determine whether CT parameters can be used to predict PFT indices. A total of 370 patients with COPD were grouped based on disease severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-IV criteria. Emphysema index (EI), air-trapping index, and airway parameters such as the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10) were measured using automatic segmentation software. Clinical characteristics including PFT results and quantitative CT parameters according to GOLD criteria were compared using ANOVA. The correlations between CT parameters and PFT indices, including the ratio of forced expiratory volume in one second to forced vital capacity (FEV₁/FVC) and FEV₁, were assessed. To evaluate whether CT parameters can be used to predict PFT indices, multiple linear regression analyses were performed for all patients, Group 1 (GOLD I and II), and Group 2 (GOLD III and IV). Pulmonary function deteriorated with increase in disease severity according to the GOLD criteria ( < 0.001). Parenchymal attenuation parameters were significantly worse in patients with higher GOLD stages ( < 0.001), and Pi10 was highest for patients with GOLD III (4.41 ± 0.94 mm). Airway parameters were nonlinearly correlated with PFT results, and Pi10 demonstrated mild correlation with FEV₁/FVC in patients with GOLD II and III ( = 0.16, = 0.06 and = 0.21, = 0.04, respectively). Parenchymal attenuation parameters, airway parameters, EI, and Pi10 were identified as predictors of FEV₁/FVC for the entire study sample and for Group 1 (R² = 0.38 and 0.22, respectively; < 0.001). However, only parenchymal attenuation parameter, EI, was identified as a predictor of FEV₁/FVC for Group 2 (R² = 0.37, < 0.001). Similar results were obtained for FEV₁. Airway and parenchymal attenuation parameters are independent predictors of pulmonary function in patients with mild COPD, whereas parenchymal attenuation parameters are dominant independent predictors of pulmonary function in patients with severe COPD.